Abstract:We invert for the upper-mantle temperatures of the Chinese continent in the depth range of 70 240 km from a recent S-velocity model. The depth where temperatures intersect a mantle adiabat with a potential temperature of ˜1300 °C is in close correspondence with the top of the seismic low velocity zone for most regions. This correspondence implies that seismic lithosphere estimated from short-time scale seismic information may be equivalent to the long-time scale geodynamical lithosphere. Defining the 1300 °C adiabat as coinciding with the lithospheric base, we estimate the seismic-thermal lithosphere thickness. The estimated thickness shows obvious dependence on the tectonic settings. Beneath eastern China, which mainly belongs to the circum-Pacific tectonic domain, it has a thickness of ˜100 km; and beneath the Qinghai Tibet plateau and south to the Tarim craton, which belong to the Tethyan tectonic domain it has a thickness of ˜160 220 km. The lithospheric thicknesses of the three large para-platforms/cratons range from ˜170 km for the western Yangtze, ˜140 km for Tarim, and ˜100 km for Sino-Korean. The three cratons may have been reshaped by Phanerozoic tectonic activities and are thinner than most cratons in other continents.
